package com.johnny.dataStructures.stack;


import java.util.Scanner;

//定义一个ArrayStack 表示类
class ArrayStack {
    private int maxSiz;//栈的大小
    private int[] stack; //数组，数组模拟栈，数据就放在该数组
    private int top = -1; //top表示栈顶，初始化为-1

    //构造器
    public ArrayStack(int maxSiz) {
        this.maxSiz = maxSiz;
        stack = new int[this.maxSiz];
    }

    //栈满
    public boolean isFull() {
        return top == maxSiz - 1;
    }

    //栈空
    public boolean isEmpty() {
        return top == -1;
    }

    //入栈-push
    public void push(int value) {
        if (isFull()) {
            System.out.println("栈满");
            return;
        }
        top++;
        stack[top] = value;
    }

    //出栈-pop，将栈顶的数据返回
    public int pop() {
        //先判断栈是否为空
        if (isEmpty()) {
            //抛出异常
            throw new RuntimeException("栈空，没有数据");
        }
        int value = stack[top];
        top--;
        return value;
    }

    //遍历栈 ,遍历时，需要从栈顶开始显示
    public void list() {
        if (isEmpty()) {
            System.out.println("栈空,没有数据~~");
            return;
        }
        for (int i = top; i >= 0; i--) {
            System.out.printf("stack[%d]=%d\n", i, stack[i]);
        }
    }
}

public class ArrayStackDemo {
    public static void main(String[] args) {
        //测试ArrayStack是否正确
        //先创建一个ArrayStack对象
        ArrayStack stack = new ArrayStack(4);
        int key;
        boolean loop = true; //控制是否退出菜单
        Scanner scanner = new Scanner(System.in);

        while (loop) {
            System.out.println("1 show: 表示显示栈");
            System.out.println("2 push: 表示添加数据到栈(入栈)");
            System.out.println("3 pop: 表示从栈取出数据(出栈)");
            System.out.println("4 exit: 退出程序");
            System.out.println("请输入你的选择");
            key = Integer.parseInt(scanner.next());
            switch (key) {
                case 1:
                    stack.list();
                    break;
                case 2:
                    System.out.println("请输入一个数");
                    int value = scanner.nextInt();
                    stack.push(value);
                    break;
                case 3:
                    try {
                        int res = stack.pop();
                        System.out.printf("出栈的数据是 %d\n", res);
                    } catch (Exception e) {
                        System.out.println(e.getMessage());
                    }
                    break;
                case 4:
                    scanner.close();
                    loop = false;
                    break;
                default:
                    break;
            }
        }
        System.out.println("程序退出");
    }
}
